1. Industrial Field
The present invention relates to a liquid crystal display and, more particularly, to a holding structure of its driving circuit substrate.
2. Prior Art
In conventional liquid crystal displays, a holding structure of a driving circuit substrate shown in FIGS. 3(a), (b) and (c) is known. In FIG. 3(a), a driving circuit substrate 12 placed between a metal box member 11 and a mold box member 17 mounted with a back light source is held by a conductive elastic spacer 13 inserted between the metal box member 11 and the driving substrate 12, and the driving circuit substrate 12 is grounded to the metal box member 11 through this spacer 13.
In FIG. 3(b), the driving circuit substrate 12 is held between a cut-and-hung-down portion 11c formed in the metal box member 11 and the mold box member 17, the driving circuit substrate 12 is secured with a screw 16, and the driving circuit substrate 12 is grounded to the metal box member 11.
In FIG. 3(c), the metal box member 11 is provided with a cut-and-hung-down portion 11d, the driving circuit substrate 12 is held between the cut-and-hung-down portion 11d and the mold box member 17, and the driving circuit substrate 12 is grounded to the metal box member 11 through the cut-and-hung-down portion 11d. 
The holding and grounding structure in FIG. 3(a) has a problem wherein the conductive elastic spacer 13 is essentially required. Therefore, not only required number of parts is increased but also the modulus of elasticity of the conductive elastic spacer 13 varies due to application of heat. As a result, holding and grounding of the driving circuit substrate 12 and the metal box member 11 become uncertain.
The holding and grounding structure in FIG. 3(b) has a problem wherein the driving circuit substrate 12 is secured with the screw 16. Therefore, when some external force such as an impact is applied thereto, the driving circuit substrate 12 cannot follow behavior of a liquid crystal panel 14, stress concentration takes place at a TCP (a Tape Carrier Package) 15 where the liquid crystal panel 14 and the driving circuit substrate 12 are connected, and the TCP, which is a weak portion, is broken, eventually resulting in malfunction of the liquid crystal display.
The holding and grounding structure in FIG. 3(c) has a problem wherein it is difficult to control size of the cut-and-hung-down portion 11d of the metal box member 11, and holding and grounding of the driving circuit substrate 12 and the metal box member 11 become uncertain.
As described above, any of the conventional structures has problems such as uncertainty of grounding of the driving circuit substrate and the metal box member, increase in number of the parts, decrease in machinery strength, and so on.
The present invention was made to solve the above-discussed problems incidental to the prior art and has an object of providing a liquid crystal display in which unnecessary stress on the connecting portion between the driving circuit substrate and the liquid crystal panel is relaxed to the utmost and the driving circuit substrate is securely grounded to the metal box member.
A liquid crystal display according to the invention possesses at least a metal box member, a mold box member with a back light source, and a driving circuit substrate for driving a liquid crystal panel held by these two cage bodies, wherein the driving circuit substrate is held between a convex portion formed in one of the foregoing two cage bodies and an elastic pressing portion formed in the other box member, the driving circuit substrate is grounded to the metal box member through this holding portion, and the driving circuit substrate is held without being secured.
It is preferable that a portion where the elastic pressing portion contacts the driving circuit substrate is convex.
Other objects, features and advantages of the invention will become apparent in the course of the following description with reference to the accompanying drawings.